Soldier in a fresco, Church of the Brontochion, Mistra, Greece

Soldier from a fresco in the Church of the Brontochion, Mistra, executed shortly after 1449 and thought to depict Constantine XI.
The accuracy of the very traditional equipment portrayed is impossible to determine since we know virtually nothing about 15th century Byzantine armour.
Note he carries a small circular shield; though uncommon, these never entirely disappeared amongst Byzantine cavalrymen.